STOCK-BASED COMPENSATION, Stock-Based Compensation - Additional Information (Details) (USD $) In Thousands, except Share data, unless otherwise specified		9 Months Ended			9 Months Ended			0 Months Ended		9 Months Ended		9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Stock Options	Sep. 30, 2014 Restricted Stock	Dec. 31, 2013 Restricted Stock	Sep. 30, 2014 Service-Based Awards	Sep. 30, 2014 Performance-Based Awards	Dec. 31, 2013 Performance-Based Awards	Jan. 11, 2012 2012 Directors Plan	Jan. 11, 2012 2012 Directors Plan	Sep. 30, 2014 2012 Directors Plan Restricted Stock	Sep. 30, 2014 2012 Plan	Sep. 30, 2014 2012 Plan Stock Options	Sep. 30, 2014 2012 Plan Restricted Stock Units (RSUs)	Sep. 30, 2014 2006 Plan Maximum	Sep. 30, 2014 2006 Plan Stock Options
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares authorized to be reserved for issuance (in shares)									600,000
2012 Directors Plan expiration period								10 years
Common stock shares available for issuance (in shares)											4,761,397
Common stock shares subject to outstanding awards that expire or terminate that are available for awards to be granted (in shares)														1,975,437
Options issued expiration period															10 years
Aggregate grant-date fair value of stock options												$ 32,414
Stock options vesting term												4 years
Underlying options, in shares	35,515
Unrecognized compensation cost, net of forfeitures		45,182
Weighted average remaining contractual term, exercisable		5 years 4 months 26 days
Weighted average remaining contractual term, outstanding		8 years 10 months
Non-vested common stock shares issued (in shares)										7,738
Restricted stock issued, value at grant date										325
Total unrecognized compensation cost related to non-vested share-based compensation awards granted						12,586				360			1,771
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition		2 years 0 months 19 days			1 year 9 months	1 year 10 months				1 year 6 months 16 days			2 years 3 months 17 days
Deferred compensation, shares issued													70,500
Deferred compensation arrangement, fair value of shares issued													2,085
Stock options issued (in shares)			432,356		354,118	376,966
Stock options issued, grant date fair value					14,590
Underlying service-based awards, unvested and outstanding (in shares)			693,003	344,928	556,240	329,818	0
Underlying options, value at grant date					$ 18,779